The Devil You Know
by Lolapola
Summary: Just how did Moriarty end up chained inside Sherlock's mind palace like that? A few months after the fall, Sherlock is forced to face the demons in his mind.


Sherlock raised his head warily. Where was he? He'd been running….it was dark….something had hit him…. He couldn't see anything. Panic seized him momentarily. Had he gone blind? He dismissed the thought immediately, along with the irrational fear. _Don't be stupid. Examine at your surroundings._

He listened carefully to the voice. The voice of reason that, of late, had started to sound like John. He always listened to that voice. _Look around. _Dark, dark….was it getting lighter? He felt so lost.

_Lost in the darkness, _a voice whispered – a voice that was certainly not John's. It was lilting, toxic, and he shook his head to dispel it. He didn't want to hear that voice ever again. _Focus! What can you see? _Ah, John. Good to have you back. He realised, rather belatedly, that he was curled in a ball against what was probably a wall. Where the hell was he? It had been too dark to see anything when he had woken up, but he could swear it was getting lighter.

_What can you last remember?_ Sherlock tried again to think at John's instruction. A case…no, Moriarty's network! Of course, he had been working on infiltrating Moriarty's network…and he'd been…caught? That bit was fuzzy. Was he running away from someone? He shook his head in frustration. Why couldn't he remember?

He turned slightly to look around the room. It was by now light enough to see. A plain concrete room, a spiral staircase at the other side of it…..it was all strangely familiar to Sherlock. Why? _Oh for God's sake, Sherlock, think!_

Then he realised what had been hitting him in the face ever since he'd woken up. Of course. Obvious. Stupid, stupid, stupid. He was in his mind palace.

It took a second for Sherlock to realise this probably wasn't good. It meant he was probably injured, unconscious, drugged…He sighed heavily. It wasn't like he could do much now. There wasn't any form of his subconscious floating about and telling him what to do, so it was possible he wasn't in any real danger. And Mycroft was monitoring him, so he could step in if need be.

He felt a little surprised at himself as he was coming to these conclusions – he was not normally this relaxed about a lack of control over a situation, but then again, everything was always easier in his mind palace. Calmer. He might as well take a chance to look around, get to know his mind again. He'd barely been here since….

_Since you left me alone. _Not now, John. He pushed the guilt away. There wasn't anything he could do about that now.

He got up and looked around the room more carefully. It seemed so…dingy. He remembered his mind being brighter, morning sunshine streaming through windows into clean rooms. Now it was all darkness and a silence that was suffocating, instead of comforting.

Sherlock climbed the staircase into the room above and found it much the same. What had happened here? A thought occurred to him, and he shivered uneasily. What if his mind palace had become so dark and unhappy because he no longer had John?

He felt angry with himself as soon as he thought of it, but the idea wouldn't go away. Sentiment. It helped no one.

_You can keep telling yourself that, Sherlock, but look around. Clearly your mind misses me, even if you don't want to. _

Sherlock leant against a wall heavily. There was no point in lying to your subconscious whilst inside your subconscious. Leaving John had been…difficult. More so than he had expected. But he didn't want to think about that now. All of this was for John. And if he was to die, it would be in the action of protecting him.

He'd promised himself that that day in the graveyard as he'd watched his friend grieve. Even if he couldn't protect John from the emotional harm that he couldn't understand or predict, he would protect him from physical harm until the day that he died.

A noise drew him out of his thoughts. He turned, peering into the shadows, a feeling of apprehension rising in him. It was an odd thing, to be so unfamiliar with your own mind.

"Hello?" he whispered, feeling foolish. He should be able to lighten the room with a thought, draw whatever it is out of the shadows with a flick of his hand – but he didn't feel like he had control over this place any more.

A shape moved in the darkness, and Sherlock tried to control his irrational fear. He was in his mind palace. Nothing could hurt him here. The shape moved closer until it was recognisable as a person.

"Who are you?" The shape didn't answer, but slowly lifted its head into the light.

Sheer terror bolted through Sherlock and he scrambled away desperately, all but cowering in the corner.

"No!" he yelled, "Not you! Not you! You're dead! You died right in front of me!"

Moriarty tilted his head and smiled his empty smile. "I did, didn't I? Funny how things work out, isn't it?"

Sherlock looked on in horror as Moriarty crept out of the shadows. He looked more insane than he ever had in real life – blood and sweat were smeared on his face, and his clothes hung in rags on a skeletal-like frame.

"Please," he whispered, not quite sure who he was pleading with, "Why is he here? Why him? Please, make him leave, make him leave…" Why not John?

Moriarty giggled. "Did you really think I would ever let you go? Did you think I'd set you free? I'm afraid that's where you're wrong, _my dear_," he hissed, and shot closer to Sherlock, backing him into a corner until they were millimetres away from each other. "You will _never_ get away from me, Sherlock."

Sherlock pulled his face away from Moriarty's as far as he could, heart pounding. Why had he ever thought he was safe in his subconscious? If Moriarty was here, that meant he would never be safe here. That meant that his enemy had been right, and they were the same. _I am you_, a voice whispered in his memory. _You are me._

_No._ Sherlock had never been so glad to hear John's voice. _No, not you. You are not the same as him. You will never be him. _

Determination rose up in him, and he met Moriarty's gaze. "All you are," he spat, "is a figment of my subconscious. A face in my memory. I can destroy you with a thought."

Moriarty smirked. "Am I not what you see in the mirror? What you've become? As long as you're alive, I will still be here. Hiding. Waiting. Every time you fall asleep, there I'll be."

Sherlock got to his feet. He refused to cower on the floor in front of his own mind. "You are just the end of a nightmare, a dying scream," he hissed, "I don't need you to survive like you need me. I promise, I will _end _you."

Moriarty shrieked a laugh from where he still crouched on the floor, startling him. "No, no, no, no, no!" he cried in his sing song voice, "Wrong, Sherlock! This will never end! I am the nightmare that goes on and on and ON! I'm here to stay, my dear!"

Moriarty leapt to his feet and seized Sherlock's face in his hands, still laughing. "You can't control me," he sang, his voice getting shriller, "I live inside that HUGE brain of yours! Can you feel me? Infecting your thoughts, always here, alwaysalwaysalwaysalways -"

"No!" Sherlock threw Moriarty away from him, but the madman only stumbled a few feet and laughed harder.

"Here's the punchline, Sherlock!" he screeched, "They will _never _be able to separate Sherlock Holmes from Jim Moriarty!"

"It's over now, Moriarty! Time to die!"

"But which one of us? You or me?"

Sherlock shook his head desperately. "If I die, so do you!"

"Wrong again! You'll die and I'll become you!"

"Stop this!" Sherlock yelled frantically. This wasn't happening. It wasn't real, it was all in his head… "Leave me alone!"

"Can't you see? You _are_ me!"

"No! I -"

"And I am you! You are Moriarty!"

Sherlock's head was spinning. Was this what it felt like to go insane? It felt as if the walls were getting smaller…and since this was all in his head, that was entirely possible. He had to get out. It wasn't safe. He had to get away from…himself?

"Forever!" Moriarty shrieked.

Sherlock seized Moriarty by his skinny neck and threw him down the stairs, into the room below. "Get out! Get out of my head and rot in hell!"

He sprinted out of the room, away from the nightmare that plagued him. He had to wake up. Whatever was happening, he needed to be awake now. But however fast he ran, he couldn't not hear the sing song voice that floated up from the cellar.

"I'll see you there, Sherlock!"

LINEBREAKLINEBREAKLINEBREAKLINEBREAKLINEBREAKLINEBREAK

Sherlock shot awake, breathing heavily. "Ah, Sherlock," a lazy voice welcomed him, "Nice of you to join us."

Sherlock looked around wildly, taking in his surroundings in a second. _Hospital. Private. Switzerland. Late afternoon. Been here one – no, two days. _His eyes narrowed. _Mycroft._

His brother was sitting beside him, looking at him condescendingly. "You were found unconscious in enemy territory. I hope you realise how fortunate it was that it was my man that found you, not the man you were looking for, otherwise you would probably be dead. Care to enlighten me on what happened?"

Sherlock paid his brother no attention. What the hell had happened in his mind palace?

"You know, Sherlock, I can't be there to bail you out every time. You're going to have to…" Mycroft trailed off, noticing apparently for the first time that Sherlock was not calming down, and if anything was becoming more agitated. He frowned and leant forward. It was not like his little brother to lose his composure so easily.

"Sherlock," he said in a lower voice than before, with a gentle tone that he only ever used on his little brother, "What's the matter?" 

Sherlock met his eyes without hesitation, a sign to Mycroft that something was seriously wrong. "Moriarty," Sherlock breathed, trying and failing to keep the edge of panic out of his voice, "He's in my mind palace. He's got control."

Mycroft leant back and ran his hand over his face, and for a moment Sherlock could see exhaustion, sadness…fear? But the mask was back up in a second, and his brother was all business again.

"Sherlock, listen to me."

Sherlock listened. It was rare moment, but one that had happened several times in his life. He desperately needed his big brother. Mycroft was the only one who could help. Mycroft was the only one who understood. He needed the guidance of the brother whom he remembered from his childhood, not the ice man. So he listened.

"There is a part of you that has taken the form of Moriarty. You cannot let that part of yourself run wild in your mind. It could ruin everything you've worked for. You must regain control."

"_How_?" 

"Go back into your mind palace. Find him. Lock him up in the darkest corner of your mind and never set him free. _Do whatever it takes._"

Sherlock nodded and leant back onto the hospital bed. "And if he escapes?"

Mycroft smiled dangerously. "He won't."

As Sherlock sank into his subconscious one more, Mycroft let the smile slide off his face and reached out to gently smooth back his brother's wild hair. "Or I will have to stop you myself," he whispered into the silence.


End file.
